The University of Illinois is a renowned research institution that has had brilliant professors as its employees. Research done at this facility is often groundbreaking and changes conventional scientific thought. One such professor was Harold Rollin Wanless, a geology professor who discovered cyclothems. . He married Grace Rogers in 1926 had a son, Harold Rogers Wanless, who received a Ph.D. in geology at The John Hopkins University. The aim of this website is to inform both geology students and non-geology students about one of the university’s greatest geology professors and give an explanation of his most significant discovery: cyclothems. This paper incudes a section on Wanless’ early life, his research, his career, and his time at U of I. A brief explanation of sedimentology and stratigraphy as well as transgressive sequences is given so that non-geology majors can understand the summaries of two of Wanless’ papers which is also included.